Solar power dynamic glass for heating and cooling buildings

ABSTRACT

Various embodiments herein relate to systems for powering electrochromic windows in a building. Systems may include photovoltaic panels configured to generate electrical power, energy storage device(s) configured for storing generated power, and one or more controllers on a network of electrochromic windows that are configured to receive power from the energy storage device(s) and power tint transitions in one or more electrochromic windows. Systems may include various additional circuit components described herein for regulating and/or controlling the generation, storage, and application of electric power. The systems and techniques described herein can be used to design networks of electrochromic windows that are hybrid-solar or off-the-grid (“OTG”).

CROSS-REFERENCE TO RELATED APPLICATIONS

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

BACKGROUND

Electrochromism is a phenomenon in which a material exhibits areversible electrochemically-mediated change in an optical property whenplaced in a different electronic state, typically by being subjected toa voltage change. The optical property is typically one or more ofcolor, transmittance, absorbance, and reflectance.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial and other uses as thin film coatings on the windowglass. The color, transmittance, absorbance, and/or reflectance of suchwindows may be changed by inducing a change in the electrochromicmaterial, for example, electrochromic windows are windows that can bedarkened or lightened electronically. A small voltage applied to anelectrochromic device of the window will cause them to darken; reversingthe voltage polarity causes them to lighten. This capability allowscontrol of the amount of light that passes through the windows, andpresents an opportunity for electrochromic windows to be used asenergy-saving devices.

While electrochromism was discovered in the 1960's, electrochromicdevices, and particularly electrochromic windows, still, unfortunately,suffer various problems and have not begun to realize their fullcommercial potential despite many recent advancements in electrochromictechnology, apparatus and related methods of making and/or usingelectrochromic devices.

SUMMARY

One aspect of the present disclosure pertains to a system for providingpower to a plurality of optically switchable windows in a building. Thesystem includes: (a) a photovoltaic array having one or morephotovoltaic panels to generate electric power; (b) a photovoltaicmonitor coupled the photovoltaic array and configured to gatherirradiance data from the photovoltaic panel(s); (c) an energy storagedevice; (d) a voltage regulator configured to receive electric powerfrom the photovoltaic array, apply a charge signal to the energy storagedevice, and generate a DC output signal using power stored in the energystorage device and/or power from the photovolatic array; (e) a networkconfigured to control the tint states of the tintable windows, where thenetwork includes a master controller configured to issue instructions toone or more window controllers for controlling the tint states of thetintable windows where the instructions are based at least in part onthe gathered irradiance data; and (f) one or more control panelsconfigured to receive power from the DC output signal and provide powerto one or more window controllers.

In some embodiments of the system includes a photovoltaic combinercoupled with the photovoltaic array and the voltage regulator, where thephotovoltaic combiner is configured to minimize wiring to the voltageregulator.

In some embodiments, the master controller is configured to receivephotopic data and/or directional lux data from one or more sensors, andthe issued instructions are further based in part on the photopic dataand/or the directional lux data. Sensors for providing the photopic dataand/or directional lux data may be located in a separate building. Insome cases, a sensor is a ring sensor. In some embodiments, the systemis configured to utilize received directional lux data to reposition thephotovoltaic panels of the photovoltaic array into a direction andorientation that approximately maximizes electric power generation.

Another aspect of the present disclosure pertains to a system forproviding power to a plurality of optically switchable windows in abuilding. This system includes: (a) a photovoltaic array having one ormore photovoltaic panels, where at least one of the photovoltaic panelsis coupled with spandrel glass, and where the photovoltaic array isconfigured to generate electric power; (b) an energy storage device; (c)a voltage regulator configured to receive electric power from thephotovoltaic array, apply a charge signal to the energy storage device,and generate a DC output signal using power stored in the energy storagedevice and/or power from the photovoltaic array; (d) one or more windowcontrollers configured to control the tint states of the tintablewindows; and (e) one or more control panels configured to receive powerfrom the DC output signal and provide power to one or more windowcontrollers.

In some embodiments of the system includes a photovoltaic combinercoupled with the photovoltaic array and the voltage regulator, where thephotovoltaic combiner is configured to minimize wiring to the voltageregulator.

In some embodiments, the control panel(s) include a master controllerconfigured to issue instructions to the window controller(s) forcontrolling the tint states of the tintable windows.

The master controller may be configured to receive photopic data and/ordirectional lux data from one or more sensors, and the issuedinstructions may be based at least in part on the photopic data and/orthe directional lux data. Sensors for providing the photopic data and/ordirectional lux data may be located in a separate building. In somecases, a sensor is a ring sensor. In some embodiments, the system isconfigured to utilize received directional lux data to reposition thephotovoltaic panels of the photovoltaic array into a direction andorientation that approximately maximizes electric power generation.

In some embodiments, the system includes a photovoltaic monitor coupledto the photovoltaic array which is configured to gather irradiance dataand were the instructions based at least in part on the irradiance data.

The systems described herein in may include a photovoltaic array havingat least two photovoltaic panels that are selective to differentwavelengths of light. In some cases, differences in the selectivity ofphotovoltaic panels may be used to determine or estimate a full spectrumof solar irradiance received by the building. Differences in selectivelymay be a result of, e.g., differences in bandgap energies of thephotovoltaic panels or use of an optical filter.

The systems described herein in may include, in some embodiments, a DCdistribution panel configured to receive the DC output signal from thevoltage regulator and distribute power to the control panel(s). The DCdistribution panel may be further configured to deliver power to one ormore non-electrochromic window systems. For example, a 24-volt directcurrent (DC) distribution grid may be used for delivering power to thecontrol panel(s) and/or the non-electrochromic system(s).

The systems described herein in may include an inverter configured tointeract with a power grid and convert the DC output signal to analternating current (AC) output. In some cases, the system may includean AC distribution panel coupled to the inverter, the AC distributionpanel configured to divide and distribute the AC output to one or morecontrol panels that are configured to receive power from the ACdistribution panel and convert AC power to DC power. In some cases, theinteraction between the inverter and power grid includes the inverterfeeding power back into the power grid and the power grid providingpower to the inverter.

In some embodiments of systems described herein, the voltage regulatormay be a pulse width modulation (PWM) controller or a maximum powerpoint tracking (MPPT) controller. In some cases, the energy storagedevice includes one or more batteries configured for deep-cycleapplications. A voltage regulator may be configured to preventovercharging of the batterie(s). In some embodiments, there may be atleast two batteries located in different areas of the building, and insome embodiments, a battery may be located at a control panel. In someembodiments, an energy storage device includes a capacitor or asupercapacitor. In some embodiments, one or more window controllers mayhave a local energy storage device.

Another aspect of the present disclosure pertains to a building façadefor providing electric power. The façade includes: (a) a plurality ofoptically tintable windows; (b) a photovoltaic array including one ormore photovoltaic panels, where the photovoltaic panel(s) are coupled tospandrel glass on the building's exterior, and where the photovoltaicarray is configured to generate electric power; (c) an energy storagedevice; and a plurality of controllers configured to (i) charge theenergy storage device using the generated electric power, (ii) controlthe tint states of the tintable windows using electric power providedfrom the energy storage device and/or the photovoltaic array, and (iii)provide power to one or more building systems and/or a municipal powergrid using power provided from the energy storage device and/or thephotovoltaic array.

Another aspect of the present disclosure pertains to a building. Thebuilding includes: (a) one or more optically tintable windows; (b) aphotovoltaic array having one or more photovoltaic panels, where thephotovoltaic panel(s) are coupled to spandrel glass on the building'sexterior surface, and where the photovoltaic array is configured togenerate electric power; (b) a photovoltaic combiner coupled with thephotovoltaic array, the photovoltaic combiner configured to produce afirst direct current (DC) signal by combining the generated electricpower from the photovoltaic array; (c) an energy storage device; (d) avoltage regulator configured to receive electric power from thephotovoltaic array, apply a charge signal to the energy storage device,and generate a DC output signal using power stored in the energy storagedevice and/or power from the photovoltaic array; (e) one or more windowcontrollers configured to control the tint states of the tintablewindows; and (f) one or more control panels configured to receive powerfrom the DC output signal and provide power to the window controllers,wherein the control panel(s) are not configured to receive power from amunicipal power grid.

In some embodiments, a building may also include a photovoltaic combinercoupled with the photovoltaic array and the voltage regulator, where thephotovoltaic combiner is configured to minimize wiring to the voltageregulator.

Another aspect of the present disclosure pertains to a methodcontrolling one or more optically switchable windows in a building. Themethod includes operations of (a) monitoring electric power generated bya photovoltaic array may of one or more photovoltaic panels; (b)determining irradiance data based on the power generated by thephotovoltaic panel(s); and (c) issuing instructions to one or morewindow controllers for adjusting the optical state of the opticallyswitchable window(s), the instructions based at least in part on theirradiance data.

In some cases, at least one of the photovoltaic panel(s) is coupled withspandrel glass on the exterior of the building.

In some cases, determining the irradiance data includes determiningdirectional lux data based on the orientation of the photovoltaicpanel(s).

In some cases, the method further includes receiving photopic dataand/or directional lux data from one or more sensors. When this is thecase, the issued instructions may be based at least in part on thereceived photopic data and/or the directional lux data.

In some cases, at least one sensor is a ring sensor, and in some cases,a sensor may be located at a different building.

The method may, in some cases, include an operation of repositioning thephotovoltaic panels of the photovoltaic array into a direction andorientation that approximately maximizes electric power generation.

In some cases, adjusting the optical state of the optically switchablewindow(s) is performed using the power generated by the photovoltaicpanel(s).

These and other features of the disclosed embodiments will be describedmore fully with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of an electrochromic deviceaccording to certain embodiments.

FIG. 2 presents a block diagram of components of a communicationsnetwork for controlling functions of one or more tintable windows of abuilding.

FIGS. 3A, 3B, and 3C illustrate upstream and downstream components indifferent embodiments of a power distribution network.

FIG. 4 depicts a schematic view of one embodiment of a class 1 powerdistribution network that also acts as a communications network.

FIG. 5A depicts a schematic view of one embodiment of a class 2 powerdistribution network that may or may not also act as a communicationnetwork.

FIG. 5B depicts a schematic view of another embodiment of a class 2power distribution network utilizing a number of secondary power insertlines.

FIG. 6 depicts an example of a photovoltaic-electrochromic system thatis grid-supported or hybrid-solar.

FIG. 7 depicts an example of a photovoltaic-electrochromic system thatis off-the-grid (“OTG”).

FIG. 8A depicts an example of a PV panel and its spectral response.

FIG. 8B depicts an example of a ring sensor and its spectral response.

FIG. 9 depicts an example of a photovoltaic-electrochromic system.

DETAILED DESCRIPTION Switchable Window Technology

Typically, an “optically switchable device” is a thin film device thatchanges optical state in response to electrical input. The thin filmdevice is generally supported by some sort of substrate, e.g., glass orother transparent material. The device reversibly cycles between two ormore optical states. Switching between these states is controlled byapplying predefined current and/or voltage to the device. The devicetypically includes two thin conductive sheets that straddle at least oneoptically active layer. The electrical input driving the change inoptical state is applied to the thin conductive sheets. In certainimplementations, the input is provided by bus bars in electricalcommunication with the conductive sheets.

While the disclosure emphasizes electrochromic devices as examples ofoptically switchable devices, the disclosure is not so limited. Examplesof other types of optically switchable devices include certainelectrophoretic devices, liquid crystal devices, and the like. Opticallyswitchable devices may be provided on various optically switchableproducts, such as optically switchable windows. However, the embodimentsdisclosed herein are not limited to switchable windows. Examples ofother types of optically switchable products include mirrors, displays,and the like. In the context of this disclosure, these products aretypically provided in a non-pixelated format.

A schematic cross-section of an electrochromic device 100 in accordancewith some embodiments is shown in FIG. 1 . The electrochromic deviceincludes a substrate 102, a conductive layer (CL) 104, an electrochromiclayer (EC) 106 (sometimes also referred to as a cathodically coloringlayer or a cathodically tinting layer), an ion conducting layer orregion (IC) 108, a counter electrode layer (CE) 110 (sometimes alsoreferred to as an anodically coloring layer or anodically tintinglayer), and a conductive layer (CL) 114. Elements 104, 106, 108, 110,and 114 are collectively referred to as an electrochromic stack 120. Avoltage source 116 operable to apply an electric potential across theelectrochromic stack 120 effects the transition of the electrochromicdevice from, e.g., a clear state to a tinted state. In otherembodiments, the order of layers is reversed with respect to thesubstrate. That is, the layers are in the following order: substrate,conductive layer, counter electrode layer, ion conducting layer,electrochromic material layer, conductive layer.

In various embodiments, the ion conductor region 108 may form from aportion of the EC layer 106 and/or from a portion of the CE layer 110.In such embodiments, the electrochromic stack 120 may be deposited toinclude cathodically coloring electrochromic material (the EC layer) indirect physical contact with an anodically coloring counter electrodematerial (the CE layer). The ion conductor region 108 (sometimesreferred to as an interfacial region, or as an ion conductingsubstantially electronically insulating layer or region) may then formwhere the EC layer 106 and the CE layer 110 meet, for example throughheating and/or other processing steps. Electrochromic devices fabricatedwithout depositing a distinct ion conductor material are furtherdiscussed in U.S. patent application Ser. No. 13/462,725, filed May 2,2012, and titled “ELECTROCHROMIC DEVICES,” which is herein incorporatedby reference in its entirety.

In certain embodiments, the electrochromic device reversibly cyclesbetween a clear state and a tinted state. In the clear state, apotential is applied to the electrochromic stack 120 such that availableions in the stack that can cause the electrochromic material 106 to bein the tinted state reside primarily in the counter electrode 110. Whenthe potential applied to the electrochromic stack is reversed, the ionsare transported across the ion conducting layer 108 to theelectrochromic material 106 and cause the material to enter the tintedstate.

It should be understood that the reference to a transition between aclear state and tinted state is non-limiting and suggests only oneexample, among many, of an electrochromic transition that may beimplemented. Unless otherwise specified herein, whenever reference ismade to a clear-tinted transition, the corresponding device or processencompasses other optical state transitions such asnon-reflective-reflective, transparent-opaque, etc. Further, the terms“clear” and “bleached” refer to an optically neutral state, e.g.,untinted, transparent or translucent. Still further, unless specifiedotherwise herein, the “color” or “tint” of an electrochromic transitionis not limited to any particular wavelength or range of wavelengths. Asunderstood by those of skill in the art, the choice of appropriateelectrochromic and counter electrode materials governs the relevantoptical transition.

In certain embodiments, all of the materials making up electrochromicstack 120 are inorganic, solid (i.e., in the solid state), or bothinorganic and solid. Because organic materials tend to degrade overtime, particularly when exposed to heat and UV light as tinted buildingwindows are, inorganic materials offer the advantage of a reliableelectrochromic stack that can function for extended periods of time.Materials in the solid state also offer the advantage of not havingcontainment and leakage issues, as materials in the liquid state oftendo. It should be understood that any one or more of the layers in thestack may contain some amount of organic material, but in manyimplementations, one or more of the layers contains little or no organicmatter. The same can be said for liquids that may be present in one ormore layers in small amounts. It should also be understood that solidstate material may be deposited or otherwise formed by processesemploying liquid components such as certain processes employing sol-gelsor chemical vapor deposition.

The electrochromic device may receive power in a number of ways. Wiringand other connectors for powering electrochromic devices are furtherdiscussed in U.S. patent application Ser. No. 14/363,769 (AttorneyDocket No. VIEWP034X1), filed Jun. 6, 2014, and titled “CONNECTORS FORSMART WINDOWS,” which is herein incorporated by reference in itsentirety.

The electrochromic device is typically controlled by a windowcontroller, which may be positioned locally on or near theelectrochromic device/window that it powers. Window controllers arefurther discussed in the following Patents and Patent Applications, eachof which is herein incorporated by reference in its entirety: U.S.patent application Ser. No. 13/049,756 (Attorney Docket No. VIEWP007),filed Mar. 16, 2011, and titled “MULTIPURPOSE CONTROLLER FOR MULTISTATEWINDOWS”; U.S. Pat. No. 8,213,074 (Attorney Docket No. VIEWP008), filedMar. 16, 2011, and titled “ONBOARD CONTROLLER FOR MULTISTATE WINDOWS”;and P.C.T. Patent Application No. PCT/US15/29675 (Attorney Docket No.VIEWP049X1WO), filed May 7, 2015, and titled “CONTROL METHOD FORTINTABLE WINDOWS.”

Photovoltaics as Power Sources

Photovoltaic (“PV”) cells, or solar cells, convert solar energy intopower. A PV panel, or module, is generally a collection of PV cellsarranged such that the power output from each cell is collected andcombined. A PV array is a collection of PV panels or modules arranged informations such as, for example, series, parallel, or series/parallel.Conventional PV panels such as, for example, Grape Solar's®GS-P60-265-Fab2 or LG's NeON™ 2 LG320N1C-G4, typically produce between240-350 W peak (for example, 36 V at 8 A DC) with 16-20% ratedefficiency. Typically, PV arrays are placed atop structures such as, forexample, rooftops of buildings, for maximum exposure to solar energy,but may also be located anywhere outside of a building, such as awest-facing facade, or even on the ground.

The power generated by PV cells is in the form of DC power. ThisPV-generated power may be used to power an electrochromic (“EC”), oroptically switchable, window network installed in a building and isknown as a PV-EC system. The size of a PV array installation will dependon the load requirements, for example, peak demands in watts, and maytake into consideration, for example, battery storage requirements inkilowatts per hour. In some implementations, PV-EC systems are alsodesigned to assume that, for example, the system will need one day ofreserve power (an overcast day followed by a sunny day), and will thusrequire PV-power generation capabilities of double the daily powerconsumption of an EC window network and its associated powerdistribution network. Thus, for example, in a PV-EC system installationemploying PV panels with 20% efficiency would need approximately one PVpanel with dimensions of 1 m×2 m (or roughly 3 ft×6 ft) per 1250 ft² ofEC glass window installed. With linear project scaling, this means thatin a deployment involving 100,000 ft² of EC glass installation and 80 PVpanels, the PV array will occupy about 1440 ft² of rooftop area(assuming a rooftop installation).

Communications Network

As described above, a network of electrochromic windows may be a powerdistribution network, a communication network, or both. Many of theembodiments herein focus on power distribution networks that may or maynot also act as communication networks, and/or which may share certaincomponents with a communication network. Where it is not specified howcommunication/control information is distributed, it is assumed thatcommunication may occur through any available means. In some cases, thismay mean that communication occurs over the same wires, conduits,tie-down anchors, and/or other components used by the power distributionnetwork. In certain cases, communication may occur over some of the samewires/components as used by the power distribution network, withadditional wiring provided for communication at particular places. Insome cases, communication may occur wirelessly, alone or in combinationwith wired communication.

FIG. 2 is a block diagram of components of a communications networksystem 200 for controlling functions (e.g., transitioning to differenttint levels) of one or more tintable windows of a building, according tocertain embodiments. As explained elsewhere herein, the communicationsnetwork may be wholly or partially co-located with the powerdistribution network. System 200 may be one of the systems managed by aBuilding Management System (BMS) or may operate independently of a BMS.

System 200 includes a master window controller 202 that can send controlsignals to the tintable windows to control its functions. System 200 isdescribed in terms of a master controller for example purposes. In otherembodiments, the window control architecture may have the logic “heavylifting” configured in a more distributed fashion, i.e., where window(leaf) controllers and/or network controllers share more of thecomputing burden. Examples of distributed control systems forcontrolling optically switchable windows are described in U.S. patentapplication Ser. No. 15/334,832, titled “CONTROLLERS FOROPTICALLY-SWITCHABLE DEVICES”, and filed Oct. 26, 2016 (Attorney DocketNo. VIEWP084); U.S. patent application Ser. No. 15/623,237, titled“MONITORING SITES CONTAINING SWITCHABLE OPTICAL DEVICES ANDCONTROLLERS,” and filed Jun. 14, 2017 (Attorney Docket No. VIEWP061C1);and U.S. patent application Ser. No. 15/691,468, titled “MONITORINGSITES CONTAINING SWITCHABLE OPTICAL DEVICES AND CONTROLLERS,” and filedAug. 30, 2017 (Attorney Docket No. VIEWP061X1), both of which areincorporated in their entireties. System 200 also includes networkcomponents 210 in electronic communication with master window controller202. The predictive control logic, other control logic and instructionsfor controlling functions of the tintable window(s), and/or sensor datamay be communicated to the master window controller 202 through thenetwork 210. Network 210 can be a wired or wireless network. In oneembodiment, network 210 is in communication with a BMS to allow the BMSto send instructions for controlling the tintable window(s) throughnetwork 210 to the tintable window(s) in a building.

System 200 also includes electrochromic windows 207 and wall switches290, which are both in electronic communication with master windowcontroller 202. In this illustrated example, master window controller202 can send control signals to EC window(s) 207 to control the tintlevel of the tintable windows 207. Each wall switch 290 is also incommunication with EC window(s) 207 and master window controller 202. Anend user (e.g., the occupant of a room having the tintable window) canuse the wall switch 290 to control the tint level and other functions ofthe tintable electrochromic window (s) 207.

In FIG. 2 , communications network 202 is depicted as a distributednetwork of window controllers including a master network controller 203,a plurality of intermediate network controllers 205 in communicationwith the master network controller 203, and multiple end or leaf windowcontrollers 210. Each plurality of end or leaf window controllers 210 isin communication with a single intermediate network controller 205. Eachof the window controllers in the distributed network of FIG. 2 mayinclude a processor (e.g., microprocessor) and a computer-readablemedium in electrical communication with the processor.

In FIG. 2 , each leaf or end window controller 210 is in communicationwith EC window(s) 207 to control the tint level of that window. In thecase of an IGU, the leaf or end window controller 210 may be incommunication with EC windows 207 on multiple lites of the IGU controlthe tint level of the IGU. In other embodiments, each leaf or end windowcontroller 210 may be in communication with a plurality of tintablewindows. The leaf or end window controller 210 may be integrated intothe tintable window or may be separate from the tintable window that itcontrols.

Each wall switch 290 can be operated by an end user (e.g., the occupantof the room) to control the tint level and other functions of thetintable window in communication with the wall switch 290. The end usercan operate the wall switch 290 to communicate control signals to the ECwindow 207. In some cases, these signals from the wall switch 290 mayoverride signals from master window controller 202. In other cases(e.g., high demand cases), control signals from the master windowcontroller 202 may override the control signals from wall switch 290.Each wall switch 290 is also in communication with the leaf or endwindow controller 210 to send information about the control signals(e.g., time, date, tint level requested, etc.) sent from wall switch 290back to master window controller 202. In some cases, wall switches 290may be manually operated. In other cases, wall switches 290 may bewirelessly controlled by the end user using a remote device (e.g., cellphone, tablet, etc.) sending wireless communications with the controlsignals, for example, using infrared (IR), and/or radio frequency (RF)signals. In some cases, wall switches 290 may include a wirelessprotocol chip, such as Bluetooth, EnOcean, WiFi, Zigbee, and the like.Although wall switches 290 depicted in FIG. 2 are located on thewall(s), other embodiments of system 200 may have switches locatedelsewhere in the room.

Power Distribution Network

In a building that has a network of EC windows, or insulated glassunits, installed but does not have PV-power generation capabilities, thenetwork of EC windows may be powered by the main building power supply.Main building power distribution consists of various feeder and branchcircuits, where some branch circuits are configured as 120 V singlephase circuits that couple with control panels such as those by View,Inc. of Milpitas, Calif. Control panels, in turn, have the capabilitiesto power the EC window network with DC circuits meeting the requirementsof the National Electric Code (“NEC”) Article 725 class 1 power-limitedcircuits, which are generally limited to 30 V and 1000 V-A, or 24 V at 8A or 196 W per power segment and class 2 inherently or not inherentlylimited circuits, which generally are limited to 30 V and 100 V-A.Typically Article 725 class 1 power limited or class 2 circuits areachieved with the use of a stepdown transformer or an AC to DC powersupply. Control panels also house master controllers and networkcontrollers capable of issuing and relaying tint commands to EC windows,so that the EC window network can function properly. EC windowcontrollers may use class 1 or class 2 power, depending upon theinstallation specifics. Building power is supplied to a control panelfrom which power is further distributed to the EC window network.

In order to drive the EC window network, for example, an EC power supplynetwork featuring a trunk line distribution scheme such as thosecommercially available from View, Inc. of Milpitas, Calif., power issupplied from the control panel through trunk lines. Connectors alongthe trunk line system may couple trunk lines with drop lines. Drop linesthen couple with window controllers, which receive tinting instructionsfrom the master controller as well as power from the same line. Powerfrom the control panels being supplied through trunk lines, connectors,and drop lines to window controllers allow window controllers to directone or more EC windows coupled with their respective window controllerto tint to various tint states, depending on issued commands. The powersupply distribution pathway of the control panel to its windowcontrollers is collectively known as a power distribution network.Certain elements of power distribution networks will now be discussed.

Many topologies are possible for implementing a power distributionnetwork to deliver power to a plurality of electrochromic windows. Invarious embodiments herein, a power distribution network can becharacterized by at least two components: an upstream component and adownstream component. A single network can include multiple upstreamcomponents and/or multiple downstream components.

The upstream components include one or more primary power supplies(e.g., control panels) connected to the building's power supply and thecomponents (e.g., cables) that are connected to the primary powersupplies. The upstream components deliver power from the control panelor other power supply to the downstream components. The primary powersupplies are essentially the most upstream components within the powerdistribution network. In many embodiments, the number of electrochromicwindows is much higher than the number of cables used as upstreamcomponents. In other words, each upstream cable typically provides powerto many electrochromic windows and window controllers. In someembodiments, an upstream cable provides power to 3 or more switchablewindows. This topology represents a substantial improvement over networktopologies where separate cables provide power to each individual windowcontroller from the primary power supply. In such cases, the number ofpower insert lines is equal to the number of window controllers. Theseconfigurations present serious challenges related to the huge number,length, and volume of cables that need to be accommodated to supplypower to all of the window controllers/windows. For example, the primarypower supplies in such topologies must be designed to accept largenumbers of cables, which can be challenging when many electrochromicwindows are installed. Further, the labor involved in pulling such alarge number/length/volume of cables throughout a building is extensive.For these reasons, power distribution networks that use fewer upstreamcables to provide power to many electrochromic windows are advantageous.

Most of the downstream components receive power from the upstreamcomponents and deliver the power to the windows and window controllers.In many cases, the downstream components are arranged in a bus line, adaisy chain, or similar physical configuration or topology with directlyconnected window controllers. In some cases, the downstream componentsinclude drop lines, which deliver power (and in some cases communicationinformation) directly to the window controllers. Typically, a drop lineis an electrical connection between a bus line and an individual windowcontroller. In addition to various power distribution cables (bus line,drop lines, daisy chain, etc.), the downstream components typicallyinclude electrical connectors. The electrical connectors may be powerinsert connectors, drop line connectors, or other types of connectors asdescribed herein. Generally speaking, power insert connectors may beused to connect upstream power distribution cabling (e.g., power insertlines connected to a control panel) to downstream power distributioncabling (e.g., a bus line). Drop line connectors may be used to connectdrop lines to a bus line. The window controllers may be connected inseries in some implementations and in a daisy chain formation in someother implementations. The downstream components can be characterized asincluding distinct segments in some embodiments, as discussed furtherwith respect to FIG. 3C, below. The cabling used for the upstreamcomponents may be the same or different from the cabling used for thedownstream components. In some embodiments, one or more supplementalpower panels or energy wells may be provided as downstream components.In some cases, supplemental power panels may receive power from a mainbuilding supply, and may provide power to a bus line via a supplementalpower insert line. Typically, a supplemental power panel will deliverpower to the bus line at a position that is more downstream than theposition at which a primary power supply delivers power to the buslines, as explained further below.

In certain implementations, at least a portion of the downstream and/orupstream cabling may be provided in a trunk line. Briefly, a trunk lineis defined by a structural element and a positional element.Structurally, a trunk line is understood to include wires for carryingpower. In many cases, a trunk line also includes wires for carryingcommunication information, though this is not always the case. Withrespect to position, a trunk line is understood to be functionallypositioned between the control panel and the individual drop lines (orthe window controllers themselves if no drop lines are present). Droplines can tap off of the trunk line to receive power and communicationinformation. Drop lines are not considered to be part of the trunk line.In certain implementations, a trunk line may be a 5 wire cable(including one pair of wires for power, one pair of wires forcommunication, and one ground wire). Similarly, the drop lines may alsobe 5 wire cable. In some other implementations, the trunk line and/ordrop lines may be 4 wire cable (including one pair of wires for powerand one pair of wires for communication, without any separate groundwire). The trunk line may carry class 1 or class 2 power in variousembodiments. In some particular embodiments, at least a portion of thedownstream cabling (and optionally the upstream cabling) may be flatwire cabling. Where flat wire cabling is used, the drop line connectorsmay be insulation displacement connectors, which are also discussedfurther below. Flat wire cabling enables wiring systems having moreflexibility in tight spaces, as well as some benefits with cablehandling and connectivity. Cabling, connectors, and circuitry for powerdistribution networks are further discussed in U.S. patent applicationSer. No. 15/365,685, titled “POWER DISTRIBUTION NETWORKS FORELECTROCHROMIC DEVICES,” filed Nov. 30, 2016 (Attorney Docket No.VIEWP085X1), which is hereby incorporated by reference in its entirety

FIG. 3A presents a simplified view of a power distribution network fordelivering power to a plurality of electrochromic windows. The followingdescription focuses on the aspects of a power distribution networkoriginating at a control panel 302. Control panel 302 receives AC or DCelectric power from a source 350. Source 350 may be, e.g., a building'smain power supply that is connected to the electric grid, anoff-the-grid (“OTG”) system that uses solar power generated on site, ora hybrid-solar system that can provide solar power generated on-site andpower through the grid. Examples of systems and power networks that mayembody source 350 are described elsewhere herein (e.g., see FIGS. 6-8 ).Returning to FIG. 3A, the upstream components 301 include the controlpanel 302 and trunk line 306. The downstream components 305 in FIG. 3Ainclude the trunk line 306, drop lines 307, and connectors 308 betweenthe trunk line 306 and drop lines 307.

The trunk line 306 may be a single continuous cable, or it may beseveral distinct cables that join one another at the connectors 308. Inthis example, the trunk line 306 is a linear bus, with drop lines 307that connect each window controller 309 to the trunk line 306. Eachwindow controller 309 controls one or more windows 311. So, the topologydepicted in FIG. 3A is often just one portion the power distributionnetwork fed by a single control panel. Similar extensions are possiblein the topologies depicted in FIGS. 3B and 3C.

FIG. 3B presents a simplified view of another power distributionnetwork. In this example, the window controllers are connected inseries. This configuration is sometimes referred to as a daisy chain.Here, the upstream components 321 include the control panel 322 and thetrunk line 326. The downstream components 325 include at least theintermediate cabling 333 that connects the window controllers 329 and/orelectrochromic windows with one another. For clarity, the windows arenot shown. They are connected to the window controllers.

FIG. 3C illustrates an additional example of a power distributionnetwork similar to the one shown in FIG. 3A. For the sake of brevity,only the differences will be discussed. In this example, the controlpanel 302 is connected to the trunk line 306 and power insert line 335.Power insert line 335 may be referred to as a secondary power insertline. The secondary power insert line 335 connects with the trunk line306 at a more downstream position on the trunk line 306. Each trunk line306 can have one or more secondary power insert lines 335. The secondarypower insert line 335 may be provided to ensure that sufficient power isdelivered from the trunk line 306 to power all of the window controllers309 and electrochromic windows (not shown) as needed. For example,limitations on current/voltage, as well as line losses, can limit thenumber of window controllers/windows that can be powered by anindividual power insert line. To address this limitation, the controlpanel 302 may be connected with the trunk line 306 using a plurality ofpower insert lines. The maximum number of secondary power insert lines335 connected to an individual control panel 302 may be limited by theavailable power output of the control panel 302. The secondary powerinsert line 335 and supplemental power insert line 337 (discussedfurther below) typically are not considered to be part of the trunk line306.

The points at which a power insert line 335 or 337 meets the trunk line306 may be referred to as a power insert points or power insertconnectors 336 and 338. These power insert points can be understood todivide the downstream components 305 into multiple segments. In generalterms, a segment refers to a group of window controllers connectedcontiguously to a section of the network (e.g., to a span of the trunkline between adjacent power insert points), and the associated sectionof the network. In FIG. 3C, three segments are shown, with a firstsegment being defined between the point at which the control panel 302meets the trunk line 306 and the point at which the secondary powerinsert line 335 meets the trunk line 306 at power insert point 336, thesecond segment being defined between the point at which the secondarypower insert line 335 meets the trunk line 306 at power insert point 336and the point at which the supplemental power insert line 337 meets thetrunk line 306 at power insert point 338, and the third segment beingdefined between the point at which the supplemental power insert line337 meets the trunk line 306 at power insert point 338 and the end ofthe trunk line 306. In this example, each segment of the downstreamcomponents 305 includes three connectors 308, three drop lines 307,three window controllers 309, and three electrochromic windows (notshown).

While FIG. 3C shows only three electrochromic window controllers persegment of the downstream components, the number of windowcontrollers/windows between adjacent power insert points may be muchhigher. In some cases, the number of window controllers andelectrochromic windows positioned on each segment of the downstreamcomponents may be between about 10-20, or between about 20-30, orbetween about 30-40. In certain cases where the power distributionnetwork is implemented as a class 1 power-limited circuit, up to about98 window controllers/windows may be installed between adjacent powerinsert points. In certain cases where the power distribution network isimplemented as a class 2 circuit, up to about 48 windowcontrollers/windows may be installed between adjacent power insertpoints. The number of window controllers/windows that can be adequatelypowered on each segment depends on a number of factors including (i) thecurrent or power drawn by each window controller, (ii) the current orpower delivered by the upstream component cables (power insert lines),(iii) the length of the cables between adjacent window controllers and(iv) the number of windows that each controller can accommodate. Forexample, a window controller may control between one and about twentywindows, or up to about fifteen windows, or up to about ten windows, orup to about five windows.

With respect to the current or power drawn by each window controller,relatively more window controllers/windows can be accommodated on eachsegment of the downstream components when the window controllers/windowsdraw relatively less power. In certain examples, the window controllerseach draw about 2 Watts or less. With respect to the current or powerdelivered by the upstream component cables/power insert lines, upstreamcables that provide more current/power can be used to accommodaterelatively more window controllers/windows per segment of the downstreamcomponents. For example, where the upstream components deliver class 1rated power (as opposed to class 2 power), relatively more windowcontrollers/windows can be positioned on each segment of the downstreamcomponents. With respect to the length of the cables between adjacentwindow controllers, longer lengths may result in higher line losses,thereby resulting in fewer window controllers/windows that can beaccommodated on each segment.

Another difference between the power distribution network shown in FIG.3C and the one shown in FIG. 3A is that the network in FIG. 3C includesa supplemental power panel 340, sometimes referred to as a remote powerpanel. Like control panel 302, supplemental power panel 340 may receiveAC or DC electric power from the grid, an on-site PV system, or ahybrid-solar system that can provide solar power generated on-siteand/or power through the grid. While not depicted, in some embodiments,supplemental power panel 340 and control panel 302 are configured toreceive power from the same source 350. In some embodiments, source 350may include an uninterruptible power supply (“UPS”) as describedelsewhere herein. In some embodiments, supplemental power panel 340 isnot directly connected to a power source, but includes and energy well(e.g., a battery) that stores excess power which can then be used duringa period of high power demand. The supplemental power panel 340 providespower to the trunk line 306 through a supplemental power insert line 337Like the control panel 302, the supplemental power panel 340 may includecircuitry or other protections to ensure that power is provided to thetrunk line 306 at an appropriate voltage, current, etc. One differencebetween the supplemental power panel and the control panel in variouscases is that the supplemental power panel acts merely as a source ofpower, whereas the control panel may have additional components thatserve various communication and control functions for controllingoptical transitions on the electrochromic windows. Another difference isthat the supplemental power panel 340 may be positioned at a locationremote from the control panel 302. Often, the distance between thesupplemental power panel 340 and the set of windows it powers is shorterthan the distance between the control panel 302 and this same set ofwindows. This may help minimize the length of the supplemental powerinsert line 337, thereby minimizing line losses. Both the supplementalpower panel 340 and the supplemental power insert line 337 may beconsidered to be part of the downstream components 301.

The secondary power insert line 335 and supplemental power insert line337 each provide power to the trunk line 306, and can collectively bereferred to as the power insert lines. The number of power insert linesused is largely affected by the number of electrochromic windows presenton the power distribution network. Factors affecting the number ofwindow controllers/windows that can be installed between adjacent powerinsert points are discussed further above.

Because the window controllers are generally provided proximate or nearto the optically switchable windows, in the downstream portion of thetopology, relatively few cables need to originate from the controlpanel. Fewer than one cable per window emanates from the control panel.As a consequence, less labor and infrastructure is required forinstallation. For example, fewer J-hooks are required to support theweight of the cables between the control panel and the downstreamportion of the topology.

While the embodiments of FIGS. 3A-3C show only a single control paneland a single trunk line, the embodiments are not so limited. In somerelated implementations, a single control panel may be connected withmultiple trunk lines, for example, as shown in FIGS. 4, 5A, and 5B,discussed further below. In some such cases, the upstream cablingcomponents may be run in parallel with one another for at least aportion of the distance between the control panel to the downstreamcomponents. In various embodiments, separate data communication linesmay also traverse the distance from the control panel to the downstreamcomponents, though this is not essential. In these or otherimplementations, multiple control panels may be provided within abuilding, and each control panel may be connected with the primarybuilding power. The control panels may be located together in a singlelocation or dispersed throughout a building. Similarly, supplementalpower panels can be provided throughout a building as desired. In someembodiments, a power distribution network may include a single controlpanel and any number of supplemental power panels.

FIG. 4 presents an example of a combined power distribution network andcommunications network. In this example, the power distribution networkis implemented as a class 1 power-limited circuit. A class 1 controlpanel 401 is connected to 6 individual cables 402, 403, and 406. Cables402 are primary power insert cables, cables 403 are secondary powerinsert cables, and cables 406 are trunk lines with either no powerconnection, or power-limited to Class 2 levels. In this example, theprimary power insert cables 402 provide power to the initial group ofwindow controllers located between the where the primary power insertcables 402 and secondary power insert cables 403 connect with the trunkline 406. The primary power insert cables 402 connect with the trunklines 406 at power/communication integration connectors 408. In thisexample, the network includes two trunk lines 406, which are analogousto the trunk line 306 in FIG. 3A, for example. The trunk lines 406 maybe rated at about 8 A or less. Drop lines 407 connect with the trunklines 406 at drop line connectors 420, thereby providing power andcontrol information to the individual window controllers 409. Thesecondary power insert cables 403 connect with the trunk lines 406 atpower insert connectors 430. The primary and secondary power insertcables 402 and 403 carrying class 1 power may each be a particularlength, for example up to about 200 feet or up to about 350 feet. Powerinsert cables longer than this length may result in substantial linelosses in certain cases. For the sake of clarity, only a single dropline 407, window controller 409, power/communication integrationconnector 408, drop line connector 420, and power insert connector 430are labeled in FIG. 4 .

Though not shown in the figures, it is understood that each of thewindow controllers 409 is connected with at least one electrochromicwindow. Further, while FIG. 4 only shows two window controllers 409 persegment of the trunk lines 406 (the segments being defined betweenadjacent power insert points or power insert connectors), manyadditional window controllers/windows may be provided in each segment.In certain implementations, for instance, the number of windowcontrollers/windows per segment on a class 1 power distribution networkmay be at least about 10, at least about 20, or at least about 30. Invarious cases, a class 1 power distribution network may have up to about96 window controllers, each controlling one or more windows, on eachsegment of the trunk line, as suggested in FIG. 4 .

Special considerations should be taken into account to ensure safeoperation of the class 1 power distribution network. For instance, thevarious power insert lines, trunk lines, and/or drop lines carryingclass 1 power may be provided in conduit or metal raceway, and/or theymay be provided as class 1 rated cable. In some cases, differentportions of the power distribution network satisfy the class 1 safetymeasures in different ways, for example, one portion of the network mayuse class 1 rated cable while another portion of the network may useconduit or raceway to protect non-class 1 rated cable. In certainimplementations, the power insert lines and/or trunk lines in a class 1power distribution network may be rated at about 15 A and 600 V. In somecases, the power insert lines and/or trunk lines may be rated as TC-ER(tray cable-exposed run). A power-limited tray cable (PLTC) may be usedfor the power insert lines and/or trunk lines in certain cases.

Power distribution networks implemented as class 1 power-limitedcircuits can be beneficial for various reasons. For instance, class 1power-limited circuits can be used to minimize the overall length ofwiring that should be installed to provide sufficient power to all ofthe windows on the network. Although power distribution networksimplemented as class 1 power-limited circuits should meet the safetyqualifications set out in the NEC (e.g., for cables carrying class 1power, the use of class 1 rated cable, or the use of conduit or racewayto run non-class 1 rated cable), these qualifications may beparticularly easy to meet in some embodiments. For example, where a setof electrochromic windows is provided in a curtain wall, with adjacentwindows being separated by hollow mullions and/or transoms, suchmullions/transoms can provide the raceway or conduit in which non-class1 rated cable can be safely run. In other words, the curtain wallinfrastructure itself can be used to provide the safety standards setout in the NEC, at least with respect to the cables that run within thecurtain wall infrastructure. Mullions and transoms are often aluminum,though this is not required. Other materials and hollow structures usedto frame adjacent windows may be used in this same way. With respect tocables that are not positioned within the curtain wall infrastructure(e.g., upstream cables such as power insert cables, portions of a trunkline not within the curtain wall, etc.), other class 1 protections suchas conduit, raceway, or class 1 rated cable may be used.

In one example, the trunk line 406 may carry class 1 power-limitedcircuits without being rated as a class 1 cable because it enclosed in ametal raceway. The trunk line 406 can safely carry class 1 power onnon-class 1 rated cable by running the trunk line 406 through the metalmullions/transoms that form the curtain wall. In such embodiments, thepower insert lines 402 and 403 may be rated as class 1 power-limitedcircuits (in which case no additional safety measures are needed), orthey may be rated as non-class 1 (in which case the power insert linesmay be run through conduit or metal raceway to ensure safe operation).The existence of a curtain wall or similar structure where adjacentwindows are separated by hollow structures makes the use of a class 1power distribution network particularly beneficial, since non-class 1rated cable can be easily and safely used to carry class 1 power. Class1 rated cable is more expensive, larger, and therefore more challengingto install than similar non-class 1 rated cable.

It should be noted that where trunk line 406 may serve as a dedicatedcommunication line and is provided separate from the power insert lines402 and 403 (such that the trunk line 406 does not carry power), thetrunk line 406 does not need to be provided with particular safetymeasures. In other words, trunk lines 406 do not need to be class 1rated cable, nor do they need to be provided in conduit or metalraceway.

In another example where the electrochromic windows are installed in aset of punched openings (rather than together in a curtain wall), class1 rated cable may be used for the power insert lines 402 and 403. Inanother embodiment, any of the power insert lines 402 and 403 and thetrunk lines 406 may be non-class 1 rated cable provided in anappropriate conduit or raceway. In a particular example, the trunk line406 may be non-class 1 rated cable, but is provided in conduit orraceway between adjacent window controllers for windows installed inadjacent punched openings.

FIG. 5A presents an embodiment of a power distribution network that mayalso act as a communication network. Here, the power distributionnetwork is implemented as a class 2 circuit. A class 2 control panel 501is connected to two trunk lines 506. No separate communication lines areshown, and control information may either be carried over the trunklines 506, over a separate communications network (not shown) orwirelessly. The window controllers 509 connect with the trunk lines 506via drop lines 507. The drop lines 507 connect with the trunk lines 506at drop line connectors 520. The trunk lines 506 may be class 2 ratedcables. In some cases, the trunk lines 506 may be rated at about 4 A orless. Due to the class 2 nature of the power distribution network inFIG. 5A, the number of window controllers that can be installed on eachsegment of the trunk line 506 is more limited than if the network wereclass 1. If the number of window controllers/windows exceeds the powerthat can be provided by the trunk lines 506 themselves, additional powerinsert lines may be provided, as shown in FIG. 5B. In this example, upto about 32 window controllers, each controlling one or more windows,may be installed on each trunk line.

FIG. 5B presents an additional embodiment of a power distributionnetwork that may also act as a communication network. In this example,the network is implemented as a class 2 circuit. A class 2 control panel501 is connected to 8 individual cables including two trunk lines 506and six secondary power insert lines 503. Here, the trunk lines 506extend all the way to the control panel 501, and no separatecommunication line or primary power insert line is provided.Communication information may be transferred over the trunk lines 506,or through wireless means, or through a separate communication network(not shown). As such, there is no need for a power/communicationintegration connector such as the connector 408 in FIG. 4 . In a similarembodiment, separate primary power insert cables and communicationcables may be provided to bring power and communication information tothe trunk lines, as shown in FIG. 4 . Drop lines 507 connect the windowcontrollers 509 to the trunk lines 506 at the drop line connectors 520.The secondary power insert lines 503 connect with the trunk lines 506 atpower insert connectors 530.

Because the power distribution network in FIG. 4 is implemented as aclass 2 circuit, fewer window controllers/windows can be powered by eachsegment of the network, as compared to a similar power distributionnetwork implemented as a class 1 power-limited circuit. While FIG. 5Bshows only a single window controller 509 on each segment (the segmentsbeing defined between adjacent power insert points, or between a powerinsert point and the end of the trunk line 506), many additional windowsmay be provided per segment in various cases. In some examples, a class2 power distribution network may have at least about 10 or at leastabout 15 window controllers and associated electrochromic windows persegment. In certain implementations, up to about 32 window controllers(WCs), each controlling one or more associated optically switchablewindows, may be installed per segment of the network, as suggested inFIG. 5B.

Although the number of windows per segment may be limited, the class 2power distribution network may be advantageous for other reasons. Forexample, because the network is implemented as a class 2 circuit, noneof the cabling needs to meet the safety requirements of a class 1power-limited circuit. In other words, the cables can be non-class 1rated cable, and can be run without the use of conduit or metal raceway.Such class 2 power distribution networks may be particularly useful incontexts where windows are installed in a punched opening construction(as compared to a curtain wall, for example). In a typical punchedopening construction, individual windows (or small sets of windows insome cases) are installed in individual openings in the building'sconstruction. Adjacent windows (or small sets of windows) are generallyseparated by concrete or other materials that make up the buildingitself. In other words, the building construction includes a largenumber of separate openings into which windows (or sets of windows) areinstalled. By contrast, with a curtain wall, many windows are installedtogether in a large opening in the building's construction. Adjacentwindows are separated by a framing system of mullions and/or transoms,depending on the layout of the windows. While the mullions/transoms canbe used to provide class 1 safety measures (e.g., the mullions/transomsproviding the metal raceway in which non-class 1 rated wire can be runwhile safely carrying class 1 power, as described above in relation toFIG. 4 ) for implementing a class 1 power distribution network, no suchconvenient framing system is typically present between adjacent punchedopenings in a building. Therefore, in certain embodiments where a numberof electrochromic windows are installed in several individual punchedopenings, it may be advantageous to implement the power distributionnetwork as a class 2 circuit.

In some embodiments, the secondary power insert lines 503 and the trunklines 506 may be rated at about 4 A or less. In some embodiments, powerinsert lines carrying class 2 power may be limited to a particularlength, for example, no more than about 350 feet.

Any of the power distribution networks described herein can furtherinclude one or more supplemental power panels and supplemental powerinsert lines, as shown in relation to FIG. 3C. Such features can beincorporated into both class 1 and class 2 power distribution networks.

Further, any of the power distribution networks described herein canfurther include one or more local power storage units. Uninterruptiblepower supplies (“UPSs”) or energy wells may be stored at variouslocations on a power distribution network. In some cases, UPSs areincluded in a system that delivers power to one or more control panels(e.g., battery bank 605 in FIG. 6 ). In some cases, energy wells areplaced at a control panel, a supplemental control panel, along a trunkline, along a drop line, or at window controllers. The energy wells canprovide power to drive optical transitions on one or more windows. Theenergy wells effectively increase the peak power available for deliveryby the system because energy can be delivered from both the controlpanel(s) and the energy well(s) simultaneously. The energy wells can berecharged when there is excess power available on the network (e.g.,when the windows are not changing tint states such as night or when thepower being used to drive the windows is less than the power that can bedelivered by the control panel or other power supply). Analogously, withenergy wells in the power distribution network, less total power isrequired for the incoming power to the system, because of the augmentedpower supply from the energy wells. Thus, wiring for the distributionnetwork may be less or of smaller gauge and/or power requirements and/orhave less duplication or redundancy that otherwise might be necessary.

In some cases, energy wells may be used to increase the number ofelectrochromic windows that can be positioned on each segment of thedownstream components. For example, a trunk line having 20 windowsinstalled on a single segment may not be able to simultaneously powertransitions on all 20 windows. While it is relatively rare for a networkto transition all windows simultaneously, the network should be designedto handle such an event. When a command is received to transition all 20windows, much of the power may be provided by a control panel and/orsupplemental power panel. If the control panel/supplemental power panelcan only provide enough power to drive transitions on 15 windows, thepower needed to transition the remaining 5 windows may be provided byone or more energy wells. The energy wells can discharge to providepower as needed, and then can recharge via the power distributionnetwork when the power demanded by the window controllers/windowsdecreases.

In conventional electrochromic window networks, power input into thenetwork closely corresponds in time and magnitude with power deliveredby the network. The power input into the network refers to the powerdrawn by the network from a main power source (e.g., via controlpanel(s) or other source(s) within the facility). The power delivered bythe network refers to the power provided to the individualwindows/window controllers (and any related components) to drive opticaltransitions on the windows. In conventional electrochromic windownetworks, these are largely the same (except for losses occurring dueto, e.g., line loss). As such, the maximum power that can be deliveredto the windows is limited by the maximum power that can be input intothe system from the power source. However, the use of energy wellsallows for these power transfers to be decoupled to some extent. In thisway, the maximum power delivered to the windows can exceed the maximumpower input into the system. Therefore, networks that utilize energystorage wells can achieve a higher peak delivered power than similarnetworks that do not utilize such energy wells.

One advantage of the use of energy wells is that electrochromic windownetworks can be designed to operate at lower peak input power than wouldotherwise be required. The peak input power in such cases may be lowerthan the power required to simultaneously tint or untint all theelectrochromic windows on the network, while the peak output power maystill be sufficiently high to simultaneously tint or untint all thewindows.

Any type of local energy storage may be used for the energy wells.Examples include supercapacitors and batteries. The energy wells mayprovide sufficient power to drive one or more optical transitions in oneor more windows. In some cases, the energy wells may provide sufficientpower to drive an optical transition in as many as about 1, 2, 3, 5, 7,10, or 12 windows simultaneously. The energy well can discharge at arate sufficient to drive optical transitions in the relevant window(s)in its domain. The energy well may be capable of providing a particularvoltage sufficient to drive optical transitions in the relevantwindow(s). In various cases the energy well may discharge at a voltageof about 24 V. The power provided to the energy well may be DC power inmany cases. In some embodiments, the energy well may include a voltageconverter for increasing or decreasing the voltage provided to theenergy well. In other cases, the energy well outputs power at the samevoltage at which it is received. In certain cases, the energy well maybe rated as a class 1 or a class 2 device.

One example of an energy well that may be used as described herein is asupercapacitor. In certain embodiments, a supercapacitor used as anenergy well has sufficient energy and power to drive a single opticaltransition on an associated electrochromic window. The energy well maybe integrated into the associated electrochromic window, for example asa part of an individual window controller. In some other cases, theenergy well may be separate from the windows and window controllers,positioned at some point (or multiple points) along the powerdistribution network at a location where it can be used to provide powerto one or more windows on the network. Supercapacitors may be deployedfor discharge in scenarios where high power but relatively low capacityis needed such as driving a complete transition in a largeelectrochromic window, e.g., an electrochromic window having a dimensionof at least about 50 inches. In some cases, batteries andsupercapacitors are used together to complement one another. Batteriesoften deliver more energy than comparably sized supercapacitors but lesspower. In various embodiments, the supercapacitor may be recharged overthe course of about 4 minutes.

The recharging may be controlled to balance the needs of the system. Forinstance, if the network is currently using a lot of the available powerto drive optical transitions in the windows, an energy well may remainuncharged until a time when there is sufficient excess power availableto recharge the energy wells. Further, if the amount of available poweris relatively low, the energy wells may be recharged at a relativelylower rate or in increments. In other words, the speed and timing ofrecharging may be controlled to promote optimal functionality of theelectrochromic windows. In this way, a user can operate the windows asdesired on demand, and the energy wells can be recharged at times thatwill not overtax the system.

The number of energy wells used in a particular network may depend on anumber of factors including, for example, the maximum power provided bythe control panel, the number of windows per control panel, how quicklythe optical transitions are driven, the length of wiring connecting thecontrol panel to the windows, the number of wires used to connect to allthe windows, the power capacity of the energy wells, etc. Generally, themore energy that can be stored in and supplied by the energy wells, theless power output is needed from the control panel. However, the controlpanel should have an output capacity sufficient to recharge the energywells as needed.

In some implementations, an energy well is provided for each window onthe network, or for substantially each window on the network. Suchenergy wells may be implemented as part of an electrochromic window. Inother words, the energy well may be integrated into the window, forexample integrated into an IGU. In some embodiments, an energy well maybe included in a window controller, which may or may not be integratedinto the window. In another implementation, a single energy well maysupply power for a group of windows. For instance, at least one energywell may be provided for each n windows on the network, where n isbetween about 2 and about 100, or where n is between about 5 and about50, or where n is between about 10 and about 30. Energy wells arefurther described in P.C.T. Patent Application No. PCT/US16/41176(published as P.C.T. Patent Application Publication No. 2017/007841),titled “POWER MANAGEMENT FOR ELECTROCHROMIC WINDOW NETWORKS,” filed onJul. 6, 2016 (Attorney Docket No. VIEWP080WO), which is herebyincorporated by reference in its entirety

In some implementations, a power distribution network may also be acommunication network. In some implementations, a communication networkmay share certain components of the power distribution network.Communication networks are configured to provide wireline and/orwireless communication and control information to each window controller(or master controller or network controller) for the purpose ofcontrolling EC window tint states and relaying information. As mentionedpreviously, power distribution networks are further described in U.S.patent application Ser. No. 15/365,685, titled “POWER DISTRIBUTIONNETWORKS FOR ELECTROCHROMIC DEVICES,” filed Nov. 30, 2016 (AttorneyDocket No. VIEWP085X1), which is hereby incorporated by reference in itsentirety.

In a building outfitted with one or more PV arrays, instead of relyingon the main building power supply to supply power to control panels andultimately window controllers through the power distribution network,the PV array may supply power to the control panels and the powerdistribution network to control the electrochromic window network.Additionally, PV-generated irradiance data may be utilized alongsidephotopic data from other sensors to aid in electrochromic window tintdecisions for maximizing energy savings, as discussed below.

Buildings that have PV-power generation capabilities may utilize thepower distribution network of an installed electrochromic window networkto power other systems, in addition to powering the electrochromicwindow network, once design load calculations are done to determine theappropriate sizes for PV arrays and battery banks. For example, lightingsystems, HVAC systems, and other “Internet of Things” systems such assensors or entertainment systems may be supplied power by the PV arraythrough the electrochromic window power distribution network. Bypowering these ancillary systems with PV-generated power through theelectrochromic window power distribution network, the power wiringinfrastructure in a building is simplified as there is no need tointegrate the power distribution networks and required wiringinfrastructure from these different systems. Such integration of systemsalso allows the interrelated building settings, such as window tintlevel, lighting levels, and temperature levels, to work collectively tomaximize energy savings and occupant comfort seamlessly.

Photovoltaic Power Distribution and the Power Distribution Network

FIG. 6 depicts an implementation of the PV-EC system 600 configurationthat is grid-assisted or hybrid-solar. In a grid-assisted orhybrid-solar system, power is not fed back into the grid; instead, thesystem either draws no power from the grid when there is adequate solarenergy to charge the battery bank, or the system draws power from thegrid when there is not adequate solar energy to run the EC system, forexample, to transition EC window tint states or to allow a battery bankto charge from the PV system.

PV array 601 is comprised of a plurality of PV panels 602. PV array 601generates DC power from sunlight. As mentioned, PV panels typicallyproduce between 240-350 W peak (36 V at 8 A DC) with 16-20% efficiency,are arranged in such a way so as to minimize IR loss in the DCconductors, and are chosen in quantities that allow for battery bank 605to charge, for example, in a day's time. The DC power generated by eachPV panel 602 is collected and combined via PV combiner 603 in order tominimize the wiring to voltage regulator/charger 604, sometimes referredto as a voltage manager, although PV combiner 603 may not be required insmaller installations. The DC power is then supplied to voltageregulator/charger 604 (e.g., a pulse width modulation (“PWM”) charger),which regulates the DC current from PV array 601 when charging batterybank 605 and prevents battery bank 605 from overcharging. Battery bank605 is made of one or more batteries that are designed for deep-cycleapplications such as storing and discharging energy for a PV system.Battery bank 605 is utilized to store energy that can be used to, e.g.,allow EC window transitions before dawn or dark dusk, or on days ofvariable cloud cover when PV-power generation may be low, thusminimizing energy drawn from grid 607. It should be understood that abattery bank 605 need not be an electrochemical cell, but may be anydevice used for storing energy. In some cases, battery bank 605 is acombination of one or more batteries, one or more capacitors, one ormore supercapacitors, or any combination thereof. Battery bank 605 mayact as an uninterruptible power supply (“UPS”) for the window network,by providing stored power when, e.g., solar power is not being generatedand/or there is an outage to an electric grid. Because electrochromicwindows, such as View, Incorporated's dynamic glass windows, may requireonly a few volts to transition between tint states, and even lessvoltage to maintain any particular tint state, battery bank 605 may besufficient to run the electrochromic window system for many days withoutthe need for energy input from the photovoltaic system. One embodimentis such a system as described herein, where the battery bank isconfigured to supply, by itself, the window system's power needs forbetween about 1 day and about 30 days, or for between about 1 day andabout 14 days, or between about 1 day and about 7 days.

Inverter 607 takes the DC power from voltage regulator/charger 604 andchanges it to AC power, typically 24-600 V DC to 120/240 V AC. Inverter607 is sized for peak power draw and includes an automatic switch to usepower from grid 608 if the batteries in battery bank 605 are not fullycharged. If need be, grid 608 provides AC power to the PV-EC system 600through inverter 607 to allow for battery bank 605 to charge and/orprovide power for window transitions. This can be useful in situationssuch as when there are multiple overcast days in a row that hamperPV-power generation. AC power from inverter 607 is supplied todistribution panel 609, which safely divides inverter AC power outputinto sub-circuits to feed to individual control panels 606. Controlpanels 606 have switch-mode power supplies (“SMPS”) that change the ACpower from distribution panel 609 into DC power, for example, 24 V,which then feeds this DC power through the power distribution networkultimately to window controllers.

Examples of power distribution topologies from control panels to windowcontrollers are described elsewhere with reference to FIGS. 3A-3C, 4,and 5A-5B. In some implementations, PV-EC system 600 may be used toprovide PV-generated AC power to other building systems, and in somecases power may be fed back into grid 608—e.g., when the power supplyexceeds power demand and battery bank 605 is at a full state of charge.

In some implementations, voltage regulator/charger 604, battery bank605, inverter 607, and PV monitor 610 may collectively be referred to aspower management module 611. PV monitor 610 observes and collectsreal-time PV data such as solar irradiance data, PV-power generationdata, and sensor data, discussed below, through Ethernet, serial, orother communications interfaces, which is then read and processed by themaster controller housed within a control panel. Power management module611 provides end-to-end integration of the system from the PV-powergeneration and sensing rooftop components, discussed below, through thecontrol logic that drives the system performance, to the EC windownetwork as they mitigate heat and glare throughout the day at the sourceof heat and glare in a building—the building facade.

FIG. 7 depicts an implementation of a PV-EC system 700 that directlyconnects the DC power from the PV array to the power distributionnetwork of the EC window network, allowing for distribution of lowvoltage DC to EC window network control components. PV-EC system 700 isconsidered “off the grid,” meaning that it does not rely on grid 607 forany power.

PV-EC system 700 operates similarly to PV-EC system 600, except insteadof supplying DC power to inverter 607 voltage regulator 704 can provideDC power directly to one or more control panels 706 and/or battery bank705. In larger systems, a DC distribution panel 709 may be used todistribute power to a plurality of panels. Voltage regulator 704 may bea maximum power point tracking “MPPT” charge manager such as the ConextMPPT 80-600 by Schneider Electric which converts a signal that ishigh-voltage and low-current to a signal that is low-voltage andhigh-current to optimize the efficiency at which solar power can bestored in battery bank 705. The voltage produced by PV array 701 mayvary depending on factors such as time of day, time of year, ambient airtemperature, and temperature of the PV array. Similarly, the optimalvoltage for charging a battery bank 705 may vary based on factors suchas the state of charge and the state of health of the battery bank. TheMMPT charge manager checks the voltage produced by the PV module and thevoltage of battery bank 705 to determine the best charging voltage thatwill result in the maximum current being transferred to battery bank705. The MMPT charge manager may also be used to provide a specifiedvoltage used by a DC distribution panel 709, a control panels 706,and/or other connected systems. In some embodiments, an MMPT chargemanager may provide 24V DC directly to control panels 706 which is thenrouted to one or more window controllers. Unlike control panels 606which may convert 120V AC to 24V DC, control panels 706 are providedwith DC and dow not need to perform an AC to DC conversion.

PV-EC system 700 avoids power loss when compared with PV-EC system 600,where inverter 607 changes the DC power from voltage regulator/charger604 to AC power and when the control panel 606 changes the AC power fromdistribution panel 609 to DC power. By eliminating these DC-ACconversions at inverter 607 and AC-DC conversions at the control panel606, about 20% less energy is lost throughout the system, with about 10%energy loss at each conversion. Without having to invert or rectifypower at any point in the system, system installation logistics simplifywithout the need to install inverter 607 in PV-EC system 700 or SMPSs incontrol panels 706 and maximum power generated by PV array 701 isavailable for system operations. PV monitor 710 and power managementmodule 711 operate in a similar fashion as their counterparts in FIG. 6, with the exception that PV monitor 710 now need only gatherinformation from MPPT charge manager 704. In some embodiments, a PVmonitor 710 may share at least some circuitry with the MMPT chargemanager 704.

Distributing 24 VDC throughout a building is becoming increasinglypopular via ceiling grid power distribution, because it is a moreefficient way to power other systems, such as, for example, lighting andsensors. For example, current commercially available low DC voltagedistribution systems, such as Ceiling Grid Power™ produced by TEConnectivity Corporation of Berwyn, Pa. and DC Flexzone Grid™ producedby Armstrong World Industries, Inc. of Lancaster, Pa. use the ceiling ofa room as a distribution point for low-voltage DC power. These systemsmay not always take into account a distribution system designed forpowering the skin of a building, for example, an EC window network, so aPV-EC system may be used as an alternative; additionally, a ceiling gridmay be used synergistically with a PV-EC system such as, for example,PV-EC system 700, to power an EC window network, lighting, and otherbuilding systems. As stated, in some implementations, the PV-EC systemmay be used to power ceiling grids that distribute power to interiorlighting and other fixtures, such as, for example, those mounted on aroom's ceiling. By powering existing low voltage ceiling power gridswith a PV-EC system such as, for example, PV-EC system 700, the ceilinggrid can be taken off the AC grid. In these implementations, power maycome from, for example, the PV array directly, the battery bank, ordistributed energy wells in a distributed energy storage system,discussed below.

Alternatively, in some implementations, power may be delivered to an ECwindow using photonic power. For example, photonic power may be beamedthrough an optical fiber or space via a laser beam and into a photonicpower converter which converts the light energy to electricity, which isused to transition the EC window via a window controller. Such systemsare further described in U.S. patent application Ser. No. 14/423,085(published as U.S. Patent Publication No. 2015/0219975), titled“PHOTONIC-POWERED EC DEVICES,” filed Aug. 23, 2013 (Attorney Docket No.VIEWP048), which is hereby incorporated by reference in its entirety andfor all purposes.

Energy Storage

FIGS. 6 and 7 depict an undistributed energy storage system for anentire building or PV-EC system site, meaning that all of the batteriesstoring from and providing power to the PV-EC system are located ingenerally one area of the system. Large energy storage systems that maybe used to power all or a sizeable portion of, e.g., a house, a buildingmay be are considered uninterruptible power supplies (“UPSs”) as theyprovide a buffer of stored energy for to provide power when PV-power isnot available and/or there is a rolling blackout. UPSs such as Tesla'sPowerwall® 2 which incorporates a charger or voltage regulator, storagein the form of Li-ion batteries, and an inverter is an example of anundistributed energy storage system which may be used for home orcommercial applications. A typical 3 bedroom house with a 6 kW PV arrayon the roof combined with two 14 kWh Powerwalls®, typically locatedcentrally together in the garage or other non-occupied space, couldessentially run entirely off-grid in certain geographic locations.Rooftop solar is becoming more common in commercial buildings for “loadsharing” to reduce consumption during peak hours when energy costs arethe highest. Some of these commercial building PV arrays are 250 kW orlarger and cover the entire roof of a building. Net zero buildings addenergy storage into the system together with rooftop PV-power generationto provide power for lighting and HVAC systems when there is no solarproduction; such systems can have a 250 kW PV system and 100 kWh energystorage systems. Storage systems are usually sized to support theovernight consumption of a building to minimize the size and expense ofthe batteries required.

In a distributed energy storage system, energy wells may be located andutilized throughout the power distribution network to aid in thedelivery of power across the power distribution network. Energy wells(e.g., located with supplemental power panels such as 340 in FIG. 3 ),may be used to increase both the peak power available to the powerdistribution network and the maximum rate at which power can bedelivered over the power distribution network. Energy wells may berecharged when there is excess power available on the network and aredesigned to have the capacity and discharge rate that is sufficientlyhigh to power at least a single tint state change on an associated ECwindow. Energy wells also allow a power distribution network to operateat lower peak input power while still meeting the peak power demand(e.g., the power required to tint or clear all EC windows in the networksimultaneously).

In a distributed energy storage system, uninterruptible power supplies(“UPSs”) may also be used to provide energy to one or more networks ofEC windows when power resources are limited, ensuring that power will beprovided to the one or more networks of EC windows during the powerresource-limited period. For example, power may be limited ingrid-assisted PV-EC systems during a full or partial grid power outagewhere the battery bank is drained during a long string of overcast days,or during a demand response for energy savings measures. In someimplementations, distributed energy storage systems replace the need fora large central battery or battery bank. Energy wells may be physicallylocated proximate to their associated window controllers in the powerdistribution network and may be in electrical communication with itsrespective window controller or controllers. When a window controller(or master controller or network controller) receives a trigger signalnotifying it of limited power resources, the window controller entersinto an intelligent power outage (“IPO”) mode. Control and tintoperations during the IPO mode are designed to extend the life of thelimited power resources, such as those available in a UPS or dedicatedenergy well, while maximizing comfort and/or safety of the building'soccupants. Generally, window controllers remain in IPO mode untilstandard operating mode can be commenced once the main power supply hasrestored its supply. UPSs are further described in U.S. patentapplication Ser. No. 15/320,725, titled “CONTROL METHODS AND SYSTEMS FORNETWORKS OF OPTICALLY SWITCHABLE WINDOWS DURING REDUCED POWERAVAILABILITY,” filed Jun. 30, 2015 (Attorney Docket No. VIEWP063), whichis hereby incorporated by reference in its entirety.

Photovoltaic Arrays as Irradiance Sensors

Aside from providing power to window controllers in an EC window networkvia a PV-EC system and power distribution network, PV panels as usedherein and thus arrays can also function as solar irradiance sensors.Solar irradiance is the measure of power per unit area, typically W/m²received from the sun. Solar irradiance measurements can includecontributions from the IR, Visible, and/or ultraviolet (“UV”) portionsof the electromagnetic spectrum. Solar irradiance may be utilized, forexample, to determine PV-generated power, incident solar heat gain,weather forecasting, and climate modeling. PV data such as solarirradiance data and PV-power generation data can be monitored by acontrol panel at the inverter, at voltage regulator/chargers, or at anMPPT charge manager (see FIGS. 6-7 ). The PV data may be transmittedthrough Ethernet, serial, or other communications interfaces, then readand processed by the master controller housed within a control panel.With a full spectrum of solar irradiance incident on a specific facadeor the roof of a building and the directional information provided byring sensors, discussed below, a PV-EC system can optimize EC windowtint state logic and control through the communications network,discussed above with relation to the power distribution network, forgoals such as maximizing building occupant comfort and energy savings.FIG. 8A depicts PV panel 801 alongside spectral response 802, showingthe spectral response of amorphous, polycrystalline, and monocrystallinetypes of PV panels. PV cells as sensors are further described in U.S.patent application Ser. No. 13/449,235 (published as U.S. PatentApplication Publication No. 2013/0271812), titled “CONTROLLINGTRANSITIONS IN OPTICALLY SWITCHABLE DEVICES,” filed Apr. 17, 2012(Attorney Docket No. VIEWP035), which is hereby incorporated byreference in its entirety and for all purposes.

Compared to point sensors or other small sensors, PV panels are lesssusceptible to false readings induced by sensors being blocked byaccumulated dirt and debris, and/or shade from a neighboring tree orstructure. Furthermore, because PV panels and arrays are constantlymonitored for PV-power generation the health of PV cells can be easilymonitored, and any deterioration in on or more PV cells can be accountedfor when determining measured solar irradiance. For example, anunexpected reduction in power generation over a period of time mayindicate degradation in performance of the PV array or panel as a sensorrather than merely a decrease in received solar irradiance. In somecases by accounting for the decreased performance of the cell, therelationship between energy generated and solar irradiance may becalibrated.

The size of a PV array may vary as necessitated by the size and locationof an installed PV-EC system, but for atypical mid-sized office buildingof about 250,000 ft², the required PV array is 500 ft². For a small lowrise office of fewer than 50,000 ft², the PV array would be about 70ft². Multiple PV arrays may be used to sense solar irradiance over avery wide area, such as, for example, over different areas of a largerooftop. In some cases, PV panels or arrays can be separated bysignificant distances to provide more accurate solar irradiationreceived at different windows and/or increase the captured solar energy.

Directionality of Solar Irradiance

Sensors designed to determine the source direction of solar radiationmay also be utilized alongside PV array irradiance sensors to aidcontrol logic for determining EC window tint states and for maximizingPV-power generation. For example, multi-sensor devices, such asorientation independent ring sensors where light sensors are positionedannularly along the exterior of a ring, may be used to accuratelydetermine solar directionality, solar irradiance, and in some cases, lux(a unit of light intensity as perceived by the human eye measured inlumens/m2). In one embodiment, one or more of the light sensors used inthe ring sensor are photopic sensors that respond to wavelengths oflight that humans are sensitive to and/or have wavelength-specificsensitivity that varies at least partially in the manner of humanvision. For example, sensors may respond only to select wavelengths oflight so that control enabled by the sensors may be correlated to humanperception of light. In certain embodiments, sensors are designed orconfigured to have such sensitivity by applying appropriate coatings tothe sensors. These ring sensors may be placed on the exterior of astructure, for example, on a rooftop, or along a building façade that isalongside or separate from the PV array. FIG. 8B depicts ring sensor 811alongside its spectral response 822. Ring sensors are further describedin U.S. patent application Ser. No. 14/998,019, titled “MULTI-SENSOR,”filed Oct. 6, 2015 (Attorney Docket No. VIEWP081) and U.S. patentapplication Ser. No. 15/287,646, titled “MULTI-SENSOR,” filed Oct. 6,2016 (Attorney Docket No. VIEWP081X1), which are hereby incorporated byreference in their entireties.

View Intelligence®, or the control logic software used to determine ECwindow tint states as executed by window controllers (or mastercontrollers or network controllers), can combine irradiance and luxmeasurements to respond to localized solar conditions such as movingclouds, overcast skies, or bright clear days. Because PV-powergeneration is also significantly influenced by more than just thevisible light spectrum, Intelligence® uses real-time PV-power generationdata as a gauge for whole sky full spectrum irradiance when paired withdirectional visible light lux data from ring sensors, thus allowing foroptimal dynamic EC window tinting.

PV-EC systems may also make use of the directional lux data and solarirradiance PV data to optimize PV-power generation, in addition tomaximizing energy savings and occupant comfort. The location andorientation of a PV array, including its angle with respect to thehorizontal and its azimuthal angle, may be rearranged with such data forincreased PV-power generation. In some implementations, the location andorientation of the PV array also accounts for sensing functions. Forexample, a building having multiple PV arrays may have them angledtoward different azimuthal directions such as one tilted south, onetilted east, and one tilted west. Furthermore, in implementations wherethe orientation of PV arrays may be mechanically repositioned,directional lux data may be used to alter the alignment of a PV arraysuch that maximum PV-power generation results due to PV arrayrepositioning its azimuthal and/or horizontal tilt.

Additionally, in some implementations, PV panels need not be positionedto optimize power generation as they are conventionally positioned. Incertain implementations, the PV panels are arranged to balance powergeneration and sensor capability. In some implementations, powergeneration and sensor capability may both be maximized. In someimplementations, power generation may be sufficient to run or charge thesystem without having been optimized for power generation and sensorfunction can be optimized by positioning of the PV panels, for example,distributing them about a wider area on a roof and at angles that mightdiffer from where one would put them for only PV power generation anddistribution.

As shown in FIG. 9 , in some embodiments, PV panels may be integratedwith or coupled with spandrels tiles and/or spandrel glass, hereinafterreferred to as photovoltaic spandrel glass. Spandrel glass is not forviewing through, but is generally used in a building to concealstructural features (e.g., columns, floors, and walls) and/or to createdesired aesthetic effect in a building. For example, large officebuildings and skyscrapers often use spandrel glass to create a seamlessand uniform exterior appearance. FIG. 9 shows a partial cut-out view ofa building with electrochromic windows 920 and photovoltaic spandrelglass which can be located, e.g., in the wall space between rooms on afloor 922, or the space between floor 924. Window controllers 926 aredepicted adjacent to each window, but this need not be the case. In someembodiments, PV spandrel glass on a building makes up at least a portionof a PV array used in a grid-supported or hybrid-solar system (e.g.,depicted in FIG. 6 ) or in OTG solar system (e.g., depicted in FIG. 7 ).In some cases, photovoltaic spandrel glass, roof-top PV arrays, andother PV systems may be separated into different systems, each of whichprovides power to, e.g., a control panel (302, FIG. 3C), a supplementalcontrol panel (340, FIG. 3C), or the grid. As described elsewhereherein, in some cases, in addition to generating electric power,photovoltaic spandrel glass can also be used to measure solarirradiance. In some cases, intelligence may account for irradiance dataprovided by photovoltaic spandrel glass in close proximity to a windowwhen controlling the window's tint state.

In some embodiments, photovoltaic spandrel includes architectural glass(e.g., glass that matches the appearance of nearby windows) covering thesurface of one or more PV cells or arrays underneath. In some cases,photovoltaic spandrel glass is made of a layered glass structure that isall solid-state and inorganic. In some cases, photovoltaic spandrelglass includes transparent PV Cells that harvest solar energy frominvisible wavelengths of light. In some cases, a photovoltaic spandrelglass may simply be a PV panel that is acceptable in appearance to abuilding owner. Use of photovoltaic spandrel glass may be ideal for,e.g., retrofit applications where a building is upgraded with anelectrochromic window network. In such cases, spandrel glass may bereplaced with photovoltaic spandrel glass which may share, at least inpart, the wiring infrastructure of power distribution networks describedherein.

Intelligence® may base its decisions to tint an EC window based on avariety of factors. For example, Intelligence® may utilize real-timeirradiance values from PV arrays, position of the sun from ring sensors,time of day and date, the EC window's current solar heat gaincoefficient (“SHGC”) which measures the solar heat transmittance throughthe window, and window properties such as window dimensions andorientation in the building, to determine what the appropriate EC windowtint level is to maximize a room occupant's comfort in a building byreducing sunlight or glare and solar heat entering the room. Forexample, if solar power generation nears or meets a seasonal maximum ordesign capacity, Intelligence® may assume that the skies are clear andthat no override is necessary. However, as solar power generationdiminishes below seasonal or design maximums, Intelligence® can respondaccordingly. Intelligence® is further described in U.S. Pat. No.9,454,055, titled “MULTIPURPOSE CONTROLLER FOR MULTISTATE WINDOWS,”filed on Mar. 16, 2011 (Attorney Docket No. VIEWP007), U.S. patentapplication Ser. No. 14/932,474 (published as U.S. Patent ApplicationPublication No. 2016/0054634), titled “MULTIPURPOSE CONTROLLER FORMULTISTATE WINDOWS,” filed on Nov. 4, 2015 (Attorney Docket No.VIEWP007C2), U.S. patent application Ser. No. 14/163,026 (published asU.S. Patent Application Publication No. 2014/0268287), titled“CONTROLLING TRANSITIONS IN OPTICALLY SWITCHABLE DEVICES,” filed on Jan.24, 2014 (Attorney Docket No. VIEWP035C1), U.S. patent application Ser.No. 14/535,080 (published as U.S. Patent Application Publication No.2015/0060648), titled “CONTROLLING TRANSITIONS IN OPTICALLY SWITCHABLEDEVICES,” filed on Nov. 6, 2014 (Attorney Docket No. VIEWP035C2), U.S.patent application Ser. No. 14/993,822 (published as U.S. PatentApplication Publication No. 2016/0124283), titled “CONTROLLINGTRANSITIONS IN OPTICALLY SWITCHABLE DEVICES,” filed on Jan. 22, 2016(Attorney Docket No. VIEWP035C3), U.S. patent application Ser. No.14/931,390 (published as U.S. Patent Application Publication No.2016/0054633), titled “CONTROLLING TRANSITIONS IN OPTICALLY SWITCHABLEDEVICES,” filed on Nov. 3, 2015 (Attorney Docket No. VIEWP035X1), U.S.Patent Application Ser. No. 13/772,969 (published as U.S. PatentApplication Publication No. 2014/0236323), titled “CONTROL METHOD FORTINTABLE WINDOWS,” filed on Feb. 21, 2013 (Attorney Docket No.VIEWP049), U.S. patent application Ser. No. 15/347,677, titled “CONTROLMETHOD FOR TINTABLE WINDOWS,” filed on Nov. 19, 2016 (Attorney DocketNo. VIEWP049X1), U.S. Patent Application No. 62/434,826, titled “CONTROLMETHOD FOR TINTABLE WINDOWS,” filed on Dec. 15, 2016 (Attorney DocketNo. VIEWP049X2), P.C.T. Patent Application No. PCT/US16/55005, titled“METHODS OF CONTROLLING MULTI-ZONE TINTABLE WINDOWS,” filed Sep. 30,2016 (Attorney Docket No. VIEWP077WO), and P.C.T. Patent Application No.PCT/US16/41344 (published as P.C.T. Patent Application Publication No.2017/007942), titled “CONTROL METHOD FOR TINTABLE WINDOWS,” filed onJul. 7, 2016 (Attorney Docket No. VIEWP086WO), which are herebyincorporated by reference in their entireties and for all purposes.

PV-EC systems may also share site monitoring data such as directionallux and solar irradiance data with other PV-EC system sites by anynetworking interfaces, such as, for example, wireline connections,wireless connections, or through cloud computing. By pooling togetherdata from multiple PV-EC system sites, PV-EC systems may learn how tobetter generate and conserve energy, predict and respond to weatherpatterns, and monitor the integrity of system components from differentsites. Site monitoring systems are further described in U.S. patentapplication Ser. No. 15/123,069, titled “MONITORING SITES CONTAININGSWITCHABLE OPTICAL DEVICES AND CONTROLLERS,” filed Mar. 5, 2015(Attorney Docket No. VIEWP061), which is hereby incorporated byreference in its entirety and for all purposes.

We claim:
 1. A system for providing power to a plurality of optically switchable windows in a building, the system comprising: photovoltaic spandrel glass comprising at least one photovoltaic array integrated with spandrels tiles and/or spandrel glass, wherein the photovoltaic array is configured to generate electric power for one or more of the plurality of optically switchable windows.
 2. The system of claim 1, further comprising an energy storage device; a voltage regulator configured to: receive electric power from the photovoltaic array and apply a charge signal to the energy storage device, and generate a DC output signal using power stored in the energy storage device and/or power from the photovoltaic array; one or more window controllers configured to control tint states of the plurality of optically switchable windows; and one or more control panels configured to receive power from the DC output signal and provide power to one or more window controllers.
 3. The system of claim 2, further comprising a photovoltaic combiner coupled with the photovoltaic array and the voltage regulator, the photovoltaic combiner configured to minimize wiring to the voltage regulator.
 4. The system of claim 2 wherein the one or more control panels comprise a master controller configured to issue instructions to the one or more window controllers for controlling the tint states of the plurality of optically switchable windows.
 5. The system of claim 4, wherein the master controller is further configured to receive photopic data and/or directional lux data from one or more sensors, and wherein the issued instructions are based at least in part on the photopic data and/or the directional lux data.
 6. The system of claim 5, wherein at least one of the one or more sensors is located in a different building.
 7. The system of claim 5, wherein the one or more sensors comprise a ring sensor.
 8. The system of claim 5, wherein the master controller is configured to receive directional lux data, and wherein the directional lux data is utilized to reposition the photovoltaic array into a direction and orientation that approximately maximizes electric power generation.
 9. The system of claim 4, further comprising a photovoltaic monitor coupled to the photovoltaic array, the photovoltaic monitor configured to gather irradiance data from the photovoltaic array, wherein the issued instructions are based at least in part on the irradiance data.
 10. The system of claim 1, wherein the photovoltaic array comprises at least two photovoltaic panels, the at least two photovoltaic panels having a different selectivity to wavelengths of light, and wherein different selectivity of the at least two photovoltaic panels is used to determine or estimate a full spectrum of solar irradiance received by the building.
 11. The system of claim 10, wherein the photovoltaic panels have a different selectivity to wavelengths of light based on their bandgap energies or an optical filter.
 12. The system of claim 2, further comprising a DC distribution panel configured to receive the DC output signal from the voltage regulator and distribute power to the one or more control panels.
 13. The system of claim 12, wherein the DC distribution panel is further configured to deliver power to one or more non-electrochromic window systems.
 14. The system of claim 13, further comprising a 24-volt direct current (DC) distribution grid for delivering power to the one or more control panels and/or the one or more non-electrochromic systems.
 15. The system of claim 2, further comprising an inverter configured to interact with a power grid and convert the DC output signal to an alternating current (AC) output.
 16. The system of claim 15, further comprising an AC distribution panel coupled to the inverter, the AC distribution panel configured to divide and distribute the AC output to one or more control panels, wherein the one or more control panels are configured to receive power from the AC distribution panel and convert AC power to DC power.
 17. The system of claim 15, wherein the interaction between the inverter and power grid includes the inverter feeding power back into the power grid and the power grid providing power to the inverter.
 18. The system of claim 2, wherein the voltage regulator is a pulse width modulation (PWM) controller or a maximum power point tracking (MPPT) controller.
 19. The system of claim 2, wherein the energy storage device comprises one or more batteries configured for deep-cycle applications.
 20. The system of claim 19, wherein the voltage regulator is configured to prevent overcharging of the one or more batteries. 